The following papers were kindly provided by two respiratory specialists
working in the UK, and deal with diagnosis and treatments. They are written
in veterinary terms and we therefore recoomend that you print them off
and take them to your vet for reference.

Chest
X-RayThe first step your vet will take will likely be a chest x-ray.
The veterinarian looks for such irregularities as: Inflammation around
the airways in the lungs (doughnuts), A flat-looking diaphragm (a healthy
diaphragm should be round), and a partial collapse of the lung. Additionally,
apart from the characteristic donut shapes you see, chronic inflammation
and/or infection will appear as white fluffy clouds on the plate. Infection
generally leads to an abundance of fluid and fluid tends to pool in the
affected area. Your vet should be sure to differentiate between fluid
associated with infection or a cardiac problem, because heart problems
may not be visible on x-ray.
However, some cats suffer both cardiac and respiratory disease combined
so if
in doubt,
your
vet should send the x-rays to a vet qualified to interprete them. Cardiac
problems can be further confirmed with EKG and/or cardiac ultrasound,
which sometimes show enlargement or valve abnormalities. .Not all asthmatic
cats lungs appear abnormal in an x-ray, however, particularly if your
cat is in the early stages of asthma.

Blood
TestsYour veterinarian will also likely take blood work. Blood work
can be useful in determining infection, because you will generally see
an elevated white blood cell count during an acute infection however,
if there has been a low grade undiagnosed infection present for some
time,
the white cell count may not be elevated at all. It can also be used
to assess raised levels of esoinopils, mast ceels, neutrophils and macrophages
all of which can be associated with respiratory disease. Blood tests
can
also check the major organ functions (liver, kidney, heart) and help
rule out other disease causes such as diabetes.

Bronchoalveolar
Lavage (BAL) The most definitive test available is the Bronchoalveolar Lavage
(BAL), which involves taking a mucus sample from the bronchioles and studying
it under a microscope to determine whether there is an increased number
of eosinophils (a type of white blood cell). This test is also useful
for ruling out lung cancer.

There
is some debate about relying on the Bronchoalveolar Lavage (BAL) when
infection is suspected. First off, if an animals lungs are in a serious
state, the anaesthetic risk needs to be very seriously weighed.

High
quality culture sampling by Specialist labs are crucial. Mycoplasma infection
is a common infection and Tetracycline antibiotics (Doxyseptin) must be
employed here. They cannot be combined with any other antibiotics and
you must ensure that the pill is swallowed because in cases where the
drug has lodged in the trachea, it causes very painful ulcers. Bordella
infection must also be ruled out, commonly known as kennel cough. These
two infections cause bronchial disease in cats and are commonly missed
by the standard lab cultures.

Infection can
exist deep in the lung and when this occurs, it can be impossible
to ever get a good sample. If there is no obvious infection present in
the mucus sample obtained, infection may be wrongly ruled out so your
vet should consider giving a short course of antibiotics to see if an
improvement is noted before proceeding to standard asthma drugs, including
steroids. Vets tend to avoid combining initial antibiotic therapy with
steroids, because steroids suppress the immune system and can therefore
interfere with the body's ability to fight infection. Studies have shown
that this suppression starts with doses as low as 5mg.

Please bear in mind though, that lung infection is actually pretty rare
in cats and when present, is usually the result of an undiagnosed underlying
respiratory disease such as Asthma or Bronchitis. These inflammatory conditions
clog the lungs with mucus and sometimes, bacteria normally filtered out
in a healthy patient, becomes trapped. It is therefore crucial that once
an infection has been treated, that the inflammatory process is halted
with aggressive therapy which can be tapered down as symptoms improve.
Untreated inflammation can permanently damage the lungs and left unchecked,
leads to scar tissue and damage to the small airway branches so therefore,
the longer the problem is left, the more long term problems the patient
is likely to have. The good news is that many cats are very well controlled
with various drugs and do go on to lead happy and healthy lives.